Earthquaker Devices Hoof

[JaviCAP]

Hi mates,

Let me show you my last build: the Earthquaker Devices Hoof.

Do this circuit remind you of anything?



Yes, it's 99% a Violet Ram Big Muff, with some interesting tweaks and mods.

The main changes in the components are:

- Q2 and Q3 are germanium. In the original, 2N1308. I've used two AC181 npn germaniums an the result is perfect. One good thing of the Bif Muff is that the HFE of the trannies is not important at all. So you have a good chance to give an use to these germs you stock and know not what to do with.

- The clippin diodes, 1N914, are changed with 5mm red leds.

- You have an aditional knob called "Shift" that is a tone / presence control, working hand in hand with the own Tone control. Very interactive these two knobs.

- Values of the pots are not the same: Sustain: B50K, Volume B1M, Tone B100K and Shift A25K.

Being a so close Big Muff clone, I was able to use one of the Mark's BMP layouts, no matter which one you choose, as you just have to swap values, and get some room for the Shift control lug  1's resistor to ground. As this effect has no protection diode, nor filtering cap, it's easy to use this holes for the resistor.

The schematics are here:

http://www.bigmuffpage.com/images/schematics/Hoof%20Schematic.jpg

The sound: You could think of a total Big Muff clon, but somehow, these tweaks and mods, offer something closer to a hot overdrive than to a Big Muff. You can dial the settings to get a BM sound, for sure, not so wild and somehow tamed, but a BM after all. But what you can really get is tons of overdriven sounds, even closer to a medium distortion.

I totally recommend this effect.  Is a real killer effect, E. Devices know what they do, and besides you can try by yourself the different tones you can get from the same schematics doing a very few changes.

Hope you like it and build one!

[GoranP]

Wow thanks Javi!

This is going right on my short 2do list!

[Harmony-Rocket]

Hey Javi,
That's G R E A T !!!
Like the hoof alot since i heard the original owned by a friend.
Perhaps you can post a stripboard layout though?
I am not sure my poor abilities are sufficient to build it without  :(

[JaviCAP]

Thank you guys!

No, I have not a vero layout, but you just have to follow this one:

http://3.bp.blogspot.com/-SZzinuajzrY/UR_Lu4KAtiI/AAAAAAAAE6E/rPAQ4ox_Wyc/s1600/EHX+73+Rams+Head+Big+Muff.png

Many of the values are correct with the Hoof layout, so you only have to:

- Change the neeeded values to fit the Hoof schematics.
- Don't put the second link from the right.
- Don't put the 100uf cap
- Take a wire from the first hole after de 4nf (6,8 in the Hoof), same row than Tone 3 and take it to the Shift pot lug 3.
- Put a 2k2 resistor from where  the 100uf positive pin is in Mark's layout to ground.
-Solder a wire from the right next hole of the upper side of this resistor to Shift lug 2.
- Replace 1n914 diodes with 5mm red leds.
-Replace Q2 and Q3 with npn germaniums.
-Replace Q1 and Q2 with 2n3904

You're done :P

BR!

[Harmony-Rocket]

Thx for the instructions Javi, I'll give it a try as soon as possible.

[Harmony-Rocket]

Hey Javi,

got one question about your advices:

"Take a wire from the first hole after the 4nf (6,8 in the Hoof),
 same row than Tone 3 and take it to the Shift pot lug3."

... that means I've got to omit the cutout? (rightside of the cap) - right?

[Harmony-Rocket]

OK - giving a look at your build it must be one the left side ....
But it seems to me - besides the 2. link from the right - you omited the huge one in the middle too
(inclusive all the cuts)......think i got it : your build is just 18x17 holes!!!

NOW it's building time!
Thanks again dude!!!

Cheers
Achim

[JaviCAP]

Oh, yes, you're right, I used the old layout, that was a bit smaller and had not the big link. As you can see, i did this at the left side (a white wire across the full board)

Mark updated the BMP layout so you had not to link two wires to ground or put an poutside link as i did, this was the layout I used, but you can do what you think best:



You have to remove (if you use the new one) the same link, the one that takes  +9v to ground trough the 100uf cap) and ommit too the external mids boost switch.

BR

[induction]

Thanks a lot, Javi!  I've been looking for a schematic for this for a while now.  I knew it was a variation on a BMP, but I didn't know the details.  I really like how it sounds, and I'll definitely build it soon.

[IvIark]

Nice one Javi, this has been in my to do list for a while but must have found it's way down the pecking order for some reason.  I'll do it soon-ish

[JaviCAP]

Thanks Mark. Don't forget to do this layout after the Mutron Micro V one :P

BR

[adstrum]

Just curious but can anyone explain why you would use red LEDs instead of 1N914 diodes.

[stringfellow_Hawke]

LEDs are diodes and can be used for clipping just like any other diode.

[adstrum]

I get that, but why would you use LEDs instead of 1N914s or any other diode? What's special about a red LED that makes it better than a 1N914 in this circuit?

[JaviCAP]

Leds have a bigger voltage drop, from 1,2v to 3,9v depending of colour and brightness, so the clippin' is different. They distort later  than a silicon (0,7v average  voltage drop)  or germanium diodes (0,3v average voltage drop), and the output is louder.

They're not better than anything, just different, as a germanium transistor is different of a silicon one being both transistors or a LM1458 is different of a AD712, being both dual opamps, but you can't say that anyone is better than the rest. Just that  one should fit better on a circuit according to taste.

BR

[adstrum]

Thanks Javi, that makes a lot of sense.

[JaviCAP]

Just a little note: I swapped the AC181 with russian MP35's, and the result is superb, so you can use this trannies with no concern.

I did see on some forums that Earthquaker devices is using latly russian npn's as original 2N1308 are gettin really hard an expensive to  get and wanted to try them.

I really love this effect, sounds increbibly fine, and you won't say that is a so close Big Muff clone.

BR

[johnk]

I just drew up a vero for the hoof and built one today. mine fit perfectly on a 17x17 vero. it sounds absolutely great and exactly like the videos posted online. I used NTE 103A's for the ge trannies. I also found that an audio (A50K) pot has a better/smoother sweep for the Fuzz control than the listed B50K (linear) one.

[johnk]

BTW, if anyone wants to build this one, here's my verified vero for it: